Automatic screw-operated press

ABSTRACT

An automatic screw-operated press in which the ram is controlled in a &#39;&#39;&#39;&#39;floating&#39;&#39;&#39;&#39; condition independently of the screw by a pair of hydraulic cylinders, and in which the screw is operated by an air cylinder the piston of which is mounted on the shiftable disk shaft, the reciprocal &#39;&#39;&#39;&#39;bumping&#39;&#39;&#39;&#39; strokes of the screw being controlled by a pair of vertically spaced proximity switches actuated by a magnetic peripheral portion of the friction wheel.

United States Patent .2.1 79,? 1 l 119295.Milli n w-i Inventors LeonardBrown;

Foster B. Cooley, both of Trenton, NJ. 882,564

Dec. 5, 1969 Sept. 14, 1971 Crossley Machine Company, Inc.

Appl. No. Filed Patented Assignee AUTOMATIC SCREW-OPERATED PRESS 7Claims, 9 Drawing Figs.

u.s. c1 25/42, 18/16 c, 25/45, 25/84 1111.01 82% 3/02 Field ofSearch25/42,43, 45,84; 18/166 References Cited UNITED STATES PATENTS 3,044,1387/1962 Lesnett et al. 25/42 3,097,411 7/1963 Gerster et al. 25/453,179,998 4/1965 Lamb 25/84 3,359,608 12/ 1 967 Walchhutter 25/45Primary Examiner-J. Spencer Overholser Assistant Examiner-Ben D. ToborABSTRACT: An automatic screw-operated press in which the ram iscontrolled in a floating" condition independently of the screw by a pairof hydraulic cylinders, and in which the screw is operated by an aircylinder the piston of which is mounted on the shiftable disk shaft, thereciprocal bumping" strokes of the screw being controlled by a pair ofvertically spaced proximity switches actuated by a magnetic peripheralPATENTEDSEPMIQII 304l076 sum 1 OF 4 .Zeonard Brown. and 1 0518). 5 C k)/N l/EN TORS flrroe NE) PATENTEDSEPMBII 3.604.076

SHEETBUFA Leona/cl Bron/l2 and Taster ;B. Cooley //V VENTO/ZS By nVh/CL/ 4 rro/aNEy AUTOMATIC SCREW-OPERATED PRESS This invention relatesto automatic screw-operated presses for compressing pulverized clay orother powdered material into tile or other compact products adaptable topress and die production.

The press of the present invention is similar in general constructionand operation to that disclosed in Miller US. Pat. No. 2,770,862, ourinvention residing primarily in two cooperative features of improvementin that press, namely, (I) control of the movements of the ram carryingthe upper multiple die unit in a "floating condition by a pair ofhydraulic cylinders, and (2) control of the multiple bumping" strokes ofthe screw by an air cylinder the piston of which is mounted on theshiftable friction disk shaft and actuated by a pair of proximityswitches mounted in vertically spaced and aligned relation adjacent tothe periphery of the horizontal friction wheel which is provided with aperipheral portion of magnetic metal or other magnetic material foractuating the switches alternately as the friction wheel is lowered orraised, for controlling the rotation of the screw in either direction.

It should be understood that in presses of the character mentioned thevalves in the hydraulic and compressed air circuits may be of variouselectrical types, and that the electrical switches controlling suchvalves may act through any of numerous relays, timers, counters andother conventionalelectrical or electronic instrumentalities assembledin coordinated relation in a control cabinet or panel, instead ofdirectly. Detail description of the construction and electrical circuitsof such instrumentalities will be omitted in this specification, sincethey form no part of the present invention.

One of the principal objects of the present invention is to providemeans in'combination with a pair of hydraulic cylinders and the pressram (1) for entirely releasing the ram from the screw into a floatingcondition, (2) thereby also enabling a sensitive initial impact of theupper multiple die unit upon the powdered material in the die cavities,and (3) enabling the ram to rise under the pressure of the air trappedin the material, as a result of the initial pressure impact of the endof the screw against the ram and upper die unit, immediately after thereversal and lifting of the screw, thereby permitting the escape of thetrapped air through clearances allowed between the upper and lower dieunits.

Another object of the invention is to provide a control of the multipleimpacts or bumps of the screw against the material in the die cavitiesin the final compacting operation on the tile or other product by meansof proximity switches, thereby eliminating the wear and tear prevalentin the levers, mechanically operated switches and other mechanicalelements previously employed in shifting the friction disks into and outof contact with the friction wheel, and also reducing the cost ofmaintenance and the delays in production caused by the resultingnecessity of repairs and replacements.

Other objects and advantages of our improvements will be apparent orpointed out in the following specification in which reference isdirected to the accompanying drawings forming a part thereof, and inwhich FIG. I is a front elevation of a screw-operated press for formingclay tile, with certain parts wholly or partly in section or removed forgreater clarity of illustration, and showing the die cavities filledwith clay dust or other powdered material;

FIG. 2 is a fragmentary view similar to FIG. 1 showing the initial lightimpact of the ram and upper die unit upon the powdered material;

FIG. 3 is a view similar to FIG. 2 showing the initial power or pressureimpact of the end of the screw on the powdered material, through the"floating" ram and impact plate therein;

FIG. 4 is a side elevation of the press shown in FIG. I, aftercompletion of a cycle of pressing operations, with the die case in itsuppermost position and with a batch of tile or other products pressed inthe previous cycle in position to be pushed onto a take-away conveyor bythe dust box at the beginning of the next cycle of pressing operations;

FIG. 5 is an enlarged detail view showing one of the hydraulic cylindersas in FIG. 1;

FIG. 6 is a detail view similar to FIG. 5 but with the hydrauliccylinder and ram controlled thereby as shown in FIG. 2;

FIG. 7 is a detail view showing the neutral relation of the proximityswitches and friction wheel as in FIG. 4;

FIG. 8 is a plan sectional view through one of the proximity switches;and

FIG. 9 is a detail section of the air cylinder, as shown in F IG. 1, foraxially shifting the friction disk shaft.

Referring to the drawings in whichlike numerals designate like parts inthe several views, it is to be understood that the various switchesindicated are connected with proper electrical relays, timers andelectrical counters of conventional design (not shown), assembled incoordinated relation in a control cabinet or panel 10 to effect thefunctions of the various valves as described hereinafter; also that thevalves indicated may be of any solenoid or other conventional electri:cal types suitable for the operational steps referred to. Therefore,detailed description of such elements and the electric circuitryinvolved will be omitted as forming no part of the present invention. 7v

The press illustrated includes a base 12 mounting a stationarylowermultiple die unit 14. A multiple impact die unit 16 depends from thelower end of a ram 18 slidably mounted on stationary rods 20 supportedon the base 12, said unit being opposed to the lower die unit 14.Laterally projecting from each side of the ram 18 is a horizontal flange22 having therein a vertical bore 24 (FIGS. 5 and 6) through whichloosely projects the piston rod 26 of a hydraulic cylinder 28. A pair ofadjustable nuts 30 is mounted on the upper threaded portion of thepiston rod in vertically spaced relation and with the lower nut belowthe flange 22, thereby leaving a substantial space between the upper nutand the top surface of the flange 22. Hydraulic fluid pipes 32 and 34are provided with electrical valves 32a and 34a, which are connectedwith cooperative elements (not shown) in the control cabinet 10 foreffecting reciprocal axial movements of piston rod 26 together with ram18 in predetermined'sequence.

A large vertical screw 36 has an intermediate threaded por tion 36aextending through a stationary bearing member 38 and a reducedunthreaded lower end portion 36b projecting through an auxiliary bearing38a into a recess 18a in theram l8 in the bottom of which is an impactplate 40. The upper end of the screw 36 is keyed or otherwise rigidlysecured to a horizontal friction wheel 42. Friction disks 44 and 46 aremounted on an axially shiftable shaft 48 which is journaled in bearings50 and 52 carried by hearing member 38. This shaft is alternatelyshifted in either axial direction by means of the piston P of an aircylinder 54 supported on the bearing member 38, said piston beingmounted directly on the friction disk shaft 48. The piston is shiftedthrough electrical valves 54a and 54b, as will hereinafter be described.Outwardly of disk 46 on shaft 48 is a pulley 56 carrying a belt 58 whichextends to a drive pulley 60 on an electric motor 62, which motor ismounted on hearing member 38. When in operation the shaft 46 is drivencontinuously in one direction.

The friction wheel 42 is of special construction, as shown more clearlyin FIGS. 4 and 7, in that it is'provided with an outer rim or annularperipheral portion 64 made of a magnetic metal or other suitablemagnetic material, and with an ex treme outer band 66 of frictionmaterial for frictional contact with the friction disks 44 and 46.

A- pair of proximity switches 68 and 70 are mounted, through a support72, on the bearing member 38 in vertically spaced and aligned relationadjacent to the vertical peripheral plane of the friction wheel 42, sothat the proximity switches will be respectively actuated when oppositethe periphery of the friction wheel. The switch element 74 of each ofthe proximity switches 68 and 70 is enclosed in a rectangular casing 69and is connected through other cooperative elements (not shown) with aircylinder valves 54a and 54b, to effect the final multiple or bumpingimpacts of the screw 36, against the impact plate 40, as willhereinafter be further described.

The Construction and operation of the die case 76 is substantially thesame as that shown and described in the Miller patent referred to, thatis, it is raised to form the die cavities C, and lowered to allowpushing of a batch of tile T or other pressed products from the dies, bymeans of an air cylinder 78 through valves 80 and 82 actuated incooperative sequence with the dust box 84 and other associatedinstrumentalities through elements (not shown) in the control cabinet10.

As shown in FIG. 4, the dust box 84, which has a sievelike bottom, isreciprocally operated in a horizontal plane on a support 86 by means ofthe piston rod 88 of a hydraulic cylinder 90, the interconnected lever92 with pairs of transversely spaced levers 94 and connecting rods 96attached to the dust box 84, the latter having on its forward end abumper 84a for pushing completed tile T from the die as will hereinafterbe described. The hydraulic cylinder 90 operated through electricalvalves 90a and 90b controlled by limit switches 98, 98a, 98b, 98c and98d mounted on a support 100 and actuated in proper sequence by a cam94a on lever 94 and cooperative with associated elements (not shown) incontrol cabinet 10.

Limit switches 102, 102b and 102d mounted on a support 104 and actuatedby contact elements 102s and 102]" carried by ram 18, and connected withvalves 54a, 54b of air cylinder 54 and also cooperative elements (notshown) in control cabinet control an initial pressure stroke of thelarge screw 36 independently of the bumping strokes controlled by theproximity switches 68 and 70, as will hereinafter be described.

With respect to the operation of the press described it should beunderstood that after being started into operation by the closing of astarting switch S on the control cabinet 10, which switch is connectedthrough cabinet 10 with a main electrical circuit (not shown), it willcontinue automatic operation in repeated cycles until stopped by theopening of the starting switch, in the same general manner as describedin the Miller patent referred to.

As shown in FIG. 4, the dust box 84 has been returned to its back orstarting position after the completion of a cycle of pressingoperations, this being effected by the tripping of electrical limitswitch 98d by cam 94a on lever 94 at the extreme end of its last forwardstroke,which actuated electrical valve 90b on hydraulic cylinder 90,thereby leaving a batch of tile T on top of bottom die unit 14 incoplanar relation with the top surface of die case 76, which will havebeen lowered by air cylinder 78 through electrical valve 80 actuated bylimit switch 90c tripped by cam 940 during the back stroke of dust box84, which stroke also opens a hinged gate 106 on hopper 108 (bymechanical means not shown) to fill the dust box with a charge ofpowdered clay I 10 or the like for the next cycle of operations.

At the extreme end of the back stroke of the dust box 84 limit switch 98will have been tripped by cam 94a, thereby automatically starting a newcycle of pressing operations by forcing the dust box forwardly to aposition over the lower multiple die unit 14 with the bumper 84a on itsfront end pushing the batch of tile T, or other products, pressed in theprevious cycle onto a take away conveyor 112. As dust box 84 reaches itsmaximum forward movement limit switch 98d is actuated by cam 94a whichenergizes electrical air valve 82 thereby causing air cylinder 78 toraise die case 76 to form multiple die cavities C (FIG. 1) above thelower die unit 14 for receiving a new charge of clay dust or otherpowdered material from the dust box 84. At the extreme end of theforward stroke of the dust box limit switch 98d is actuated therebyagain energizing valve 90b on hydraulic cylinder 90 thus reversing themovement of piston rod 88 and returning dust box 84 to its back orstarting position, as shown in FIG. 4. However, before completion of itsreversed movement the dust box, through cooperative actuation of limitswitches 98b and 980, alternately energizing valves 90a and 90b onhydraulic cylinder 90, will have been subjected to a series of short andrapid reciprocative or vibratory strokes thereby shaking the charge ofdust therein into the die cavities C, as shown in FIG. I, the extent ofthe vibratory action being controlled by a timing element (not shown) inthe control cabinet.

As the dust box 84 completes its back stroke to starting position, asshown in FIG. 4, limit switch 98, connected through control cabinet 10with electrical valves 32a and 34a on hydraulic cylinders 28 is trippedby cam 940, which applies hydraulic pressure to the upper ends of thecylinders, thereby disengaging the lower nuts 30 from the bottoms offlanges 22, thus leaving ram 18 in a floating" condition and permittingthe multiple upper die unit to be lowered at controlled speed into alight impact on the powdered material 110 in the die cavities C. Thisforces part of the air from the material in what may be called theinitial dc-airing" step, as shown in FIG. 2. As ram 18 begins itsdownward movement limit switch 102 is actuated by contact element l02fthis switch being connected through control cabinet 10 with valve 54a onair cylinder 54, the energizing of which shifts disk 44 against frictionwheel 42 causing screw 36 to follow the ram downwardly until the lowerend of the screw comes into abutment with the impact plate 40 in the ram18, thereby applying the initial power bump or pressure stroke to theclay dust or other powdered material 110 in the die cavities C, as shownin FIG. 3. This further compresses and dc-airs" the material in thecavities. Due to the floating condition of the ram 18 it will rise byreason of the force exerted by compressed air within the partiallycompressed material when released from the pressure of the end of thescrew 36, thereby permitting the escape of this air through clearancesallowed between the punchlike formations of the dies 14 and 16, thusensuring ultimate greater hardness and solidity of the tile T or otherpressed products.

Final hardness of the tile T or other pressed products is obtained byreversing screw 36 immediately after its initial impact on impact plate40 and then subjecting it to a preset plurality of pressure strokes bymeans of proximity switches 68 and 70 connected with valves 54a and 541;as previously explained. These switches are controlled by automaticelectric counters or other suitable relay and switching elements (notshown) so that as the friction wheel 42 comes into the horizontal planeof one of said switches it will cause reversal of rotation of the wheeland send it into the plane of theother switch. When the preset number ofbumping strokes has been reached the automatic counter will act throughvalves 114 on air brake cylinders 116 to stop friction wheel 42 in itsuppermost position, as shown in FIG. 1.

After the last bump" of screw 36 against ram 18 the latter is returnedto its uppermost position, as shown in FIG. I, by said counter andswitch means (not shown) acting through valves 34a on hydrauliccylinders 28 to force the lower nuts 30 on piston rods 26 into liftingengagement with the bottom surfaces of the flanges 22 on the ram. Inthis position the upper nuts 30 are spaced above the top surfaces of theflanges 22 to permit a floating" condition of the ram, as shown in FIGS.2 and 3. However, if the ram becomes stuck during its downward movementit will be freed by engagement of the upper nuts 30 with the topsurfaces of the flanges 22.

During the return of the ram 18 to its uppermost or starting positionlimit switch 102 connected with valve on air cylinder 78 is tripped,which applies air pressure to the top of the cylinder thereby loweringdie case 76 to its lowermost position, as shown in FIG. 4, and leavingthe batch of tile T or other pressed products flush with the top surfaceof the die case 76 to be pushed by dust box 84 onto takeaway conveyor112.

The automatic operation of the press will continue in repeated cyclesuntil stopped by opening of starting switch 5, as previously mentioned.

Various changes or modifications may be made in our improved features ofpress construction and operation without departing from the spirit orscope of our invention, as defined in the appended claims. Therefore, itshould be understood that the specific constructions shown and describedare intended to be illustrative only and not restrictive thereto.

We claim:

1. In an automatic screw-operated press of the type including a base, anaxially shiftable shaft journaled on said base and having a pair ofdisks fixedly mounted thereon, a friction wheel mounted horizontallybetween the opposed faces of said disks on the upper end of a verticalscrew threadedly mounted in said base for rotary and reciprocal axialmovement therein, a ram mounted for vertical movement on said base inopposed relation to the lower end of said screw for selective abuttingimpacts thereon, an upper die unit depending from said ram, a lower dieunit on said base opposed to and cooperative with said upper die unit,and means for supplying powdered material to said lower die unit; saidram having on each side thereof a laterally projecting flange providedwith a vertical bore through which projects a threaded piston rod of ahydraulic cylinder supported on said base and an adjustable nut on saidpiston rod for engagement with the bottom surface of said flange topermit lowering of the ram and upper die unit at a speed controlled by apair of electrical valves connected with said hydraulic cylinder into aninitial light impact on the powdered material in the lower die unit.

2. An automatic screw-operated press as in claim 1 and including an aircylinder having its piston mounted on said shiftable shaft for shiftingeither of the friction disks thereon against said friction wheel inefiecting axial movement of the screw in either direction; electricalswitch means actuated by the downward movement of said ram andcooperative with electrical air valves connected with said air cylinderfor effecting the downward movement of said screw into an initialpressure impact against said ram and returning it to its uppermostposition; and also including a pair of vertically spaced proximityswitches supported on said base, said switches being independentlyactuated by magnetic material in the peripheral portion of the frictionwheel as it alternately moves into coincident relation with either ofsaid switches, which are cooperative with said electrical air cylindervalves for effecting a preset plurality of pressure impact strokes ofthe end of the screw against said ram to impart final hardness to theproducts into which the powdered material in the lower die unit is beingpressed.

3. An automatic screw-operated press as in claim I and including anadditional nut on each of the threaded piston rods controlling thevertical movement of the ram, these nuts being on the outer ends of thepiston rods at a spaced distance above said lateral flanges projectingfrom said ram.

4. An automatic screw-operated press as in claim 1 in which the magneticmaterial in the peripheral portion of the friction wheel comprises anannular rim made of magnetic material, and in which said rim isencircled by a band of friction material for contact with the respectivefriction disks.

5. An automatic screw-operated press as in claim 1 and including acontact plate on said ram opposed to the lower end of the screw.

6. An automatic screw-operated press as in claim 2 in which each of saidproximity switches includes a rectangular casing enclosing the switchelement, each of said casings being mounted in vertically spaced andaligned relation in close proximity to the plane of vertical travel ofthe periphery of the friction wheel on a stationary support attached tothe press base.

7. An automatic screw-operated press as in claim 2 in which saidproximity switches are cooperative with valves connected with aircylinders operating brakes above the friction wheel for applying saidbrakes against and stopping rotation of said friction wheel uponcompletion of said preset plurality of impact strokes of the end of thescrew against the ram.

1. In an automatic screw-operated press of the type including a base, anaxially shiftable shaft journaled on said base and having a pair ofdisks fixedly mounted thereon, a friction wheel mounted horizontallybetween the opposed faces of said disks on the upper end of a verticalscrew threadedly mounted in said base for rotary and reciprocal axialmovement therein, a ram mounted for vertical movement on said base inopposed relation to the lower end of said screw for selective abuttingimpacts thereon, an upper die unit depending from said ram, a lower dieunit on said base opposed to and cooperative with said upper die unit,and means for supplying powdered material to said lower die unit; saidram having on each side thereof a laterally projecting flange providedwith a vertical bore through which projects a threaded piston rod of ahydraulic cylinder supported on said base and an adjustable nut on saidpiston rod for engagement with the bottom surface of said flange topermit lowering of the ram and upper die unit at a speed controlled by apair of electrical valves connected with said hydraulic cylinder into aninitial light impact on the powdered material in the lower die unit. 2.An automatic screw-operated press as in claim 1 and including an aircylinder having its piston mounted on said shiftable shaft for shiftingeither of the friction disks thereon against said friction wheel ineffecting axial movement of the screw in either direction; electricalswitch means actuated by the downward movement of said ram andcooperative with electrical air valves connected with said air cylinderfor effecting the downward movement of said screw into an initialpressure impact against said ram and returning it to its uppermostposition; and also including a pair of vertically spaced proximityswitches supported on said base, said switches being independentlyactuated by magnetic material in the peripheral portion of the frictionwheel as it alternately moves into coincident relation with either ofsaid switches, which are cooperative with said electrical air cylindervalves for effecting a preset plurality of pressure impact strokes ofthe end of the screw against said ram to impart final hardness to theproducts into which the powdered material in the lower die unit is beingpressed.
 3. An automatic screw-operated press as in claim 1 andincluding an additional nut on each of the threaded piston rodscontrolling the vertical movement of the ram, these nuts being on theouter ends of the piston rods at a spaced distance above said lateralflanges projecting from said ram.
 4. An automatic screw-operated pressas in claim 1 in which the magnetic material in the peripheral portionof the friction wheel comprises an annular rim made of magneticmaterial, and in which said rim is encircled by a band of frictionmaterial for contact with the respective friction disks.
 5. An automaticscrew-operated press as in claim 1 and including a contact plate on saidram opposed to the lower end of the screw.
 6. An automaticscrew-operated press as in claim 2 in which each of said proximityswitches includes a rectangular casing enclosing the switch element,each of said casings being mounted in vertically spaced and alignedrelation in close proximity to the plane of vertical travel of theperiphery of the friction wheel on a stationary support attached to thepress base.
 7. An automatic screw-operated press as in claim 2 in whichsaid proximity switches are cooperative with valves connected with aircylinders operating brakes above the friction wheel for applying saidbrakes against and stopping rotation of said friction wheel uponcompletion of said preset plurality of impact strokes of the end of thescrew against the ram.